He added: “The message from Aldi and Lidl is that they can match the big supermarkets on price but better them on quality.

“But they remain discount supermarkets and must compete strongly at that level, too, hence the introduction of basics ranges which offer good value with even fewer frills. A common feature of the discounters is to offer three tiers of products – a kind of simplified choice structure for consumers of good, better and best.

“The big supermarkets, by comparison, will offer a much broader range in terms of brands and price categories.

“The simplicity of the discounters’ model is what makes it effective and efficient.”

A Lidl spokesman said: “We introduced the Simply range to offer customers an alternative to our premium-listed products. While our ongoing range offers tremendous value for money, we sensed there was an appetite from customers to purchase value products as part of their weekly food shop.

“Many have adopted a polarised way of shopping, choosing to buy premium products but also opt for the value option.

“The range is limited in size at the moment but it might be extended if we continue to see customers enjoying the choice it offers.”